Where to Find and Catch Toxapex
From Pokemon Go Wiki
Toxapex are found and captured in Nest and Habitat locations.
Nests
Toxapex Nests are locations that consistently spawn Toxapex.
Habitats
Toxapex Habitats are spawn locations where Toxapex is likely to be encountered, but not guaranteed the way a Nest is.
Additional Tips and Information
Best Nests
If you know a really good nest or any of the nests above is really good, list them here: